Magnetically actuated well working tool



P1138011 x1 1 saunas!) 3 R fiw Oct. 1, 1963 H. c. EHLERT 3,105,550

MAGNETICALLY ACTUATED WELL WORKING TOOL Filed Jan. 30, 1961 v sSheets-Sheet 1 Harry C. E/x/er/ IN VEN TOR.

BY @Q LLQ QJ ATTORNEY 5/; /er 1 INVENTOR.

5 Sheets-Sheet 4 BY QC/M;

Harry C.

H. C. EHLERT MAGNETICALLY ACTUATED WELL WORKING TOOL Filed Jan. 30, 1961Oct. 1, 1963 ATTO/P/Vfy Oct. 1, 1963 H. c. EHLERT 3,105,550

MAGNETICALLY ACTUATED WELL WORKING TOOL Filed Jan. 30, 1961 5Sheets-Sheet 5 C f/7/er/ INVENTOR.

5 BY QC/AL 7- ATTORNEY United States Patent 3,105,550 MAGNETICALLYACTUATED WELL WORKING TOOL Harry C. Ehlert, Houston, Tex., assignor toCameo, Incorporated, Houston, Tex., a corporation of Texas Filed Jan.30, 1961, Ser. No. 85,933 Claims. (Cl. 16665) This invention relates towell working tools to be run by wire line suspension equipment andoperated automatically at a preselected subsurface location. Moreparticularly, the invention concerns an improved tool which can bepreset for signaled operation as it traverses any selected one ofseveral subsurface signaling stations each providing a distinctivelydifferent signal but only one of which will be sensed for workperforming response of the tool in a particular selective setting.

An object of the invention is to provide a tool which can be more safelyhandled with less likelihood of premature and unintentional release ofenergy before being run into a well hole and before reaching a point atwhich signaled operation is desired.

Another object is to provide a tool whose work performance is effectedthrough control units connected in series relation for dependency on oneanother for conjoint eifectiveness and arranged for response in the caseof one unit to a given subsurface signal and in the case of the otherunit to downhole environmental conditions so that tool actuation isineffective in the absence of concurrent responses.

A further object is to provide a tool having a set of series connectedcontrol elements whose simultaneous action is required to render thetool operable for work performance and one of which elements has anactuator that normally assumes a position to disarm the operatingmechanism and is shifted to an arming position by the action thereon ofhigher than atmospheric fluid pressure encountered at downhole depths.

A still further object of the invention is to provide an electriccontrol circuit and a set of series connected circuit closing devices,one constituting a normally open arming switch arranged for closingresponse to physical conditions of environment and one or more othersinvolving a normally open switch which is highly sensitive andresponsive to a magnetic signal when under the influence thereof.

Another object is to provide a circuit controlling switch unit having apair of contacts of which one is movable toward and away from the otherwith the pivotal movement of a permanently magnetized lever fulcrumedintermediate its opposite poles and between a pair of spaced apart polepieces which co-operate with the permanent magnet for attracting thepivoted magnet in one direction of rotation about the fulcrum axis andfor causing a reverse rotational movement when the spaced apart polepieces are subjected to or come within a signaling magnetic field of apolarity for repelling the poles of the magnetized lever.

Other objects and advantages will become apparent during the course ofthe following specification having reference to the accompanyingdrawings wherein FIGS. 1 and 2 are part elevation and part verticalsectional views of tubing string fragments representative of a pair3,105,550 Patented Oct. 1, 1963 ice of vertically spaced apart signalingstations with a wire line tool illustrated in FIG. 1 in a nonresponsiverela tion to the signaling station and responsive to the signalingstation of FIG. 2 but immediately following the completion of a workperforming operation; FIGS. 3A and 3B are companion views showing oneembodiment of the tool in vertical section; FIG. 4 is a wiring diagramof the control circuit involved in the tool structure disclosed in FIGS.3A and 33; FIG. 5 is a vertical section of the magnetic switch unit withthe parts in open circuit relation; FIG. 6 is a view similar to FIG. 5but showing the contacts closed; FIGS. 7 and 8 are a vertical sectionand an elevation respectively as on lines 7--7 and 88 of FIG. 5; FIGS.9A, 9B and 9C are vertical sectional views of a modified embodiment ofthe improved tool, and FIG. 10 is a Wiring diagram illustrating thecircuitry employed in the tool as shown in FIGS. 9A, 9B and 9C.

The improved tool here disclosed is adapted for harnessing a signaledrelease of energy for performing any of various conventional downholeoperations, inclusive of the introduction of an inhibitor fluid; theperforation of tubing and the setting of well completion and flowcontrol equipment. For illustrative purposes, FIG. 1 and FIG. 2 show arunning tool by which a tool hanger assembly 1 is to be positioned andlatched at a selected depth in a tubing string 2. At each of a number ofspaced apart locations as determined upon at the time the tubing is setin the well hole, there will be located a pair of co-operating tubingsections, indicated at 3 and 4, and the section '3 is in the nature of alanding nipple having an internal keeper groove while the section 4provides for the mounting of work performing signals in given verticallyspaced relation above the keeper groove. Each signaling station isillustrated as involving a stack of separate rings retained acounterbored upper portion of the tubing section 4, the detailarrangement being best seen in FIG. 3B. As they are shown, the lowermostring 5 is of nonmagnetic material and has embedded in it a series ofpermanent magnets 6 in the nature of radially disposed bar segmentsarranged in two vertically spaced apart rows, each containing an annularsuccession of circularly spaced apart magnets. When these magnets are soarranged and the inner end faces of the magnets in one row are ofopposite polarity to the end faces of the magnets in the companion row,there will be provided between adjoining north and south poles aninwardly protruding magnetic field as a signal to which response can behad by a magneto device which traverses the field. Spaced upwardly abovethe lowermost magnet carrying ring 5 is a similar ring 5a carryingmagnets 6a in circular array and in two vertically spaced apart groupsor rows. The two magnet carrying rings preferably are identicalsubassemblies and they are to be spaced apart different distances ateach of the work performing stations. For that purpose, a series ofspacer rings, one of which is shown at 7 in FIG. 3B, are interposedbetween adjacent edges of the rings 5 and 5a. The differently spacedrelationship of the magnetic signaling fields is illustrated in FIGS. 1and 2.

Thus in FIG. 1, the wire line suspension tool 8 is illustrated asrunning past the signaling station with the laterally projectablelatching dogs of the tool hanger 1 retracted. A pair of magneto devices9 are illustrated by dotted lines in a spaced apart relation differingfrom that of the magnets in FIG. 1, so that these devices will not besimultaneously within the fields of the pair of fields at the signalingstation illustrated. The spaced apart relations of the two signalingfields and of the two magnetic field responsive magneto devices 9 areidentical in the FIG. 2 illustration or are coded to one another for thesignaled operation of the work performing tool. FIG. 2 actually showsthe relationship of the parts following completion of the operation withthe tool hanger latched in place and the running tool elevatedthereabove as at the start of elevation.

The hanger tool 1 is of a known type and involves a tubular bodyslidably mounting a reciprocable plunger and carrying laterallyprojectable dogs. Initially, the dogs are retracted and the plunger isin an upwardly projected relation to the housing and is to be fittedwithin a hollow bottom portion of the running tool 8. Shear pins 10 and11 secure the hanger housing and the plunger to the running tool. Theenergy for depressing the plunger when signaled operation occurs isprovided by an explosive charge 12 carried in the running tool andarranged to be electrically ignited. When ignition occurs, the expandinggases from the combustible charge act downwardly on a pistonlikeprojectile 13 and the force is transmitted into the plunger, first toshear the pin 11 and then to depress the plunger for expanding thelocking dogs into the keeper notch of the tubing section 3. With thehanger so latched, an upward jar on the wire line suspended tool willshear the pin 10 and allow the tool to be removed from the well.

When the source of releasable energy is an explosive charge, itsignition will be by a detonator in an electric circuit completed by theconcurrent response of the set of magneto devices 9 which, as will bedescribed in detail, comprise normally open circuit closing switch unitsin series circuit connection with one another and also with a suitablearming switch. This circuit arrangement is seen in FIG. 4, indicatingthe normally open positions of both magneto devices 9 and the armingswitch. 14. Only when the several switches are closed at the same timecan actuating current from the battery 15 reach the explosive chargedetonator 12a for igniting the charge as referred to above.

The circuit and its operating components are housed and properlypositioned in relation to one another within the tool body 8, which forconvenience is made up of a number of separately formed parts threadedtogether in end to end succession with suitable seals, such asconventional O-rings, at the several joints. Also at the variousdetachable joint couplings, there will be located detachable pin andsocket electrical connectors for completing the current fiow circuitbetween the electrical components. within the sealed chamber of the toolbody, there are shown in FIGS. 3A and 3B the pair of magneto devices 99,the battery 15 and the arming switch 14 comprising a fixedly mountedsocket member and a movable plug for travel into and out of contact withthe socket, the drawing illustrating the switch 14 as being closed andas being grounded through the wall of the body 8. The circuit componentswithin the chamber, together with a number of intervening spacer rings16-16 and 16a of insulating material, fill the hollow chamber space andproperly locate the elements in reference to each other. The set ofspacer rings indicated at 16a are of different axial dimension and canbe disposed interchangeably relative to one another. The purpose ofthese spacer rings is to enable the magneto devices 99 to be spacedapart in different relationships by substituting or compounding ofspacer rings 16a so that such spacing between the magneto devices can bemade to conform with the spacing of magnetic signaling fields at any ofthe several signaling stations. When an operation is to be performed ata given station, the tool is assembled at the surface to present itssignal actuated magneto devices 99 in a spaced relation coded to matchthat of the fields of a selected signaling station.

The movable plug of switch element 14 is mounted at the lower end of areciprocatory plunger 17 whose upper end is exposed 'by means of alateral opening 18 in the tool body 8 to pressures exteriorly of thetool. Normally, the plunger is projected upwardly from the switchclosing position shown under the elastic force of a coil spring 19interposed between the housing seat and the bottom of the piston headenlargement at the upper end of the plunger 17. The strength of thespring is selected for projecting the plunger when fluid pressures onopposite ends of the plunger are balanced. The slidable piston head issealed to the tool housing 8 as by means of an O-ring 20. When the toolis assembled at the surface, the sealed chamber and the underside of theplunger 17 will be at atmospheric pressure and the switch 14 will beheld open under the force of the spring 19 and thus will de-arm theelectric circuit so that no premature release of energy will occur dueto any unintentional or accidental closing of the switch contacts of themagneto devices 99, as might possibly occur due to jarring or otherforces.

The arrangement is such that under usual conditions of use the tool willremain in unarmed condition so long as it remains above the surface. Inthe descent of the tool in a well, well fluid pressure in excess ofsurface atmospheric pressure will tend to depress the plunger 17 againstthe force of the spring 19. When such depression occurs, the armingswitch 14 will be closed and will condition the circuit for completionwhen the magneto devices 99 traverse the magnetic fields to which themagneto devices have been coded.

Under certain conditions, it will be desirable to provide the tool body8 with a screw threaded lateral port 21 at its upper end in alignmentwith the head of the plunger 17. This threaded opening is for optionalreception of a set screw 21a which can be adjusted inwardly into hearingcontact with the head of the plunger 17 at either or both of itsopposite stroke limits. When so held at the upper stroke limit, thearming switch itself will be precluded from accidental depression. Onthe other hand, when the set screw interlocks with the piston head atthe lower limit of piston stroke, the arming switch 14 will be locked inits closed position. This latter condition may be desirable in certaininstances, as, for example, when downhole well pressures areinsuflicient for reliance to effect actuation of the arming switch. Theplunger would then be depressed by prying it downwardly with a screwdriver or other type of tool, and held by the set screw immediatelybefore lowering the tool into the tubing string.

Each magneto device 9 is preferably constructed as shown in the detailviews FIGS. 5-8. As so disclosed, the unit includes a magnetized rockerlevel 22 fulcrurned centrally of its opposite arms on a shaft 23 forrocking in opposite direction of rotation in the space between a pair ofannular pole pieces 24 and 25 secured to the top and bottom faces of apair of transversely spaced apart spacer blocks 26 and 27 of insulatingmaterial on opposite sides of the magnetized lever 22 whose axle shafthas its opposite ends mounted in the spacer blocks. The parts are heldin assembled relation by means of brass studs 28 which ass through bothof the annular rings or pole pieces 24 and 25 and the spacer blocks 26and 27. The magnetized lever 22 is constituted by a permanent magnet andas illustrated its pivot shaft 23 is mounted closer to the lower polepiece 25 than to the pole piece 24. Accordingly, whenever the swingposition of the north pole of the lever is below the horizontal plane ofthe shaft 23 as viewed in FIG. 5, the lines of force between the poleswill provide an attraction tending to rock the lever in acounterclockwise direction with the north pole moving toward the polepiece 25 and the south pole moving toward the upper pole piece 24. Astop to limit such movement is provided by an adjustable screw stud 29fitted to an insulator sleeve 30 and projected downwardly through thepole piece 24 so that its terminal tip portion is in the upward swingpath of the south pole of the pivoted lever. Directly above the northpole of the pivoted lever is an insulator sleeve 31 extending throughthe pole piece 24 and adjustably receiving the threaded stud 32 whosetip portion is to be engaged by the north pole as a stop in the path ofclockwise movement of the pivoted lever. This tip of the stud 32provides one of a pair of co-operating switch contacts, the other ofwhich contacts is indicated as a small metal wafer 33 on the upper faceof the north pole of the lever 22. A terminal connector 34 is held onthe stud 32 for its wired connection in an electric circuit to becontrolled. A similar circuit connector terminal 35 is held by afastening stud 36, which passes upwardly through the bottom pole piece25 and the spacer block 26 for contact at its tip portion with theadjacent mounted end of the supporting shaft of the magnetized rocklever 22. The stud can therefore serve as a current conductor betweenthe magnetized lever and the terminal 35 and an additional path forcurrent flow is aiforded by a flexible lead wire 37 joined at one end tothe connector terminal 35 and at its opposite end to the hub portion ofthe rock lever 22.

As before indicated, the switch contacts provided by the tip of the stud32 and the wafer 33 normally are held open by the magnetic attractionbetween the poles of the permanent magnet comprising the rock lever 22and the respective spaced apart pole pieces 24 and 25. That attractioncan be overcome by imposing on the pole pieces a magnetic field ofdifferent or, in other words, opposite polarity. Thus, as seen in FIG.6, a magnet 38 is shown positioned beside the unit with its oppositepoles arranged to co-operate with the pole pieces 24 and 25. When thesouth pole of the magnet 38 is uppermost, then the field from the magnet38 through the pole pieces 25 and 24 will tend to impart a clockwisedirection of rotation to the magnetized lever 22, whose north pole isrepelled away from the north pole of the magnet 38 and the pole piece25, while the south pole of the magnetized lever is attracted toward thebottom pole piece and is at the same time repelled away from the upperpole piece 24 and the south pole of the magnet 38. The imposition of thefield of the magnet 38 in overcoming the hold-open tendency of thepermanent magnet comprising the rock lever is instantaneous and resultsin a snap action. In like manner, removal of the field of the magnet 38from influence on the switch unit results in a quick snap-openoperation.

The degree of angular movement between open and closed positions can becontrolled by relative adjustment of the stop studs 29 and 32 andordinarily a small range of movement is to be preferred. The projectedangularly related broken lines to the right of FIGS. 5 and 6 indicaterespectively the inclination from a horizontal plane passing through thepivot axis of the lever in open position and in closed position. At bothlimits, the north pole in relation to the spaced apart pole pieces isalways closer to the bottom pole piece 25. The adjustable stop screwscould be set so that the north pole on clockwise rotation would moveabove the axis and to an extent that the magnetic lines of force of themagnet would then tend to maintain that position. For a subsequentreverse or counterclockwise movement, a magnet such as 38 but with thepoles reversed in position to present its north pole uppermost, couldthen be presented to the pole pieces 24 and 25 to restore or rock thepermanent magnet lever to its original position. Furthermore, it will beobvious that the electric circuit contacts, if desired, can betransferred from the north pole end of the lever to the south pole endof the lever for co-operation with the screw stud 29 in providing anormally closed electric switch for such situations wherein it isdesired to employ an extraneous magnetic field for opening an electriccircuit.

The same magnetic switch can be employed in a multiple stack in amodified well working tool which differs only slightly from thatheretofore described. In this instance, the stack of magnetic switchesincludes a succession of units 9a, 9b, 9c and 9d held in fixed spacedapart relation within the tool body 108. For selectively setting orcombining the switches in given pairs coded to a particular spacing ofmagnetic fields of the tubing string stations and for closing a firingcircuit on concurrent switch operation, it is here proposed to employ arotary multiple-way switch 39 by which any one of the switches 9b, or 9dmay be paired with the switch 9a. The rotary switch is to be setselectively in advance of a tool lowering operation and for that purposeit has a downwardly extending operating stem 40 carrying a sleeve orsocket 41 to receive the upper bifurcated end of a rotatable operatingshaft 42. A crosspin 43 is carried by the socket sleeve 41 to extendinteriorly thereof and to be received within the bifurcated end of thestem 42. Bevel gears connect the lower end of the stem 42 to atransverse shaft 44 having a screw driver slotted head presented at awindow in the side wall of the housing 108 and by which a manualadjustment of the rotary switch 39 is effected. For convenience, therotary switch 39, as well as other of the circuit components, provide asubassembly, all fastened to a tie strap 45 for insertion and removal asa unit within the chamber of the hollow tool body 108. Such additionalcomponents include dry cell batteries 46 and 47, a relay switch 48 and acondenser 49 associated with the coil relay 48 and the arming switch114. As in the case of the arming switch 14, the switch 114 is normallyopen and is arranged to be closed by a fluid pressure responsive plunger117 when the latter is depressed against the elastic force of the coilspring 119.

Assuming that the rotary switch 39 has been adjusted to select orcompound the switches 9a and 9b, then when these two switches areconcurrently closed at a time when the arming switch 114 also is closed,current from the battery 46 will be delivered to the coil of the relay48 for closing the firing circuit from the battery 47 to a detonator 50or other electrically responsive device whose actuation releases or setsin motion a source of work performing energy.

The circuit as shown in FIG. 10 differs from the more simple circuit ofFIG. 4 in the inclusion of a firing circuit relay 48 and condenser 49. Adefinite amount of energy is thus supplied independently of differencesin tool speed through the signaling fields. The circuit also possessesdesirable safety features, especially when the Working force to bereleased is an explosive charge. On completion of the control circuitthrough the relay coil, the capacitor charges up quickly and on reachinga minimum operating voltage, the relay responds to complete the firingcircuit to the detonator. Although the contacts of the detector unitsmay open shortly thereafter, the relay contacts remain closed because ofthe energy stored in the capacitor. Opening of the relay contacts isthus delayed until voltage across the capacitor falls below the drop-outvoltage of the relay and the time can be adjusted by varying theresistance of the relay coil, the value of the capacitor, or both. Sincethe capacitor requires time to charge, premature firing is prevented inthe event the detector units are jarred closed momentarily. The use of adouble pole relay and on-off switch effects grounding of the triggeringterminals at all times other than when the relay switch is actuated.Accordingly, premature firing is avoided upon internal malfunctioning orotherwise.

In use of the tool having its magneto devices in given axially spacedapart relation and in coded or matching correspondence with the spacingof the magnets at any selected signaling station of a tubing string andwith the arming switch preconditioned for action, the tool is loweredthrough the tubing string and automatically actuated upon reaching theknown depth of the preselected station. During tool descent, the switchcontrolled circuit remains open so long as less than all of the seriesconnected switches are closed. One or more but not all of the switchesat the same time may close at various tool positions above the selectedstation; as, for example, sufficient well hole pressure to close thearming switch may exist at a depth higher than the selected station andindividual magneto devices will respond but not in unison during atraverse of magnetic fields at those magnets whose spaced apart relationdiffers from the spacing between the magneto devices. Only when travelof the tool brings it into the selected station in the tubing stringwill axial spacing between the magneto devices 9-9 match or coincidewith the axial spacing of the magnetic fields for the concurrentinfluencing of the magneto devices of the set and the resultingsimultaneous switch closing action. Such occurrence with the armingswitch also closed establishes the condition in which all of the seriesconnected switches are instantly closed for completing the electricalcircuit and directing current flow to fire the explosive charge.

What is claimed is:

1. In a well working tool for travel through a tubing string havingspaced apart stations each providing signaling means distinctly unlikeothers, said tool comprising a body, a source of working energy carriedby the tool body, means mounted by the tool body and responsive tostation signaling means upon traverse thereof and arranged to be presetfor effective response solely to the signaling means of a preselectedstation, other means active in response to well subsurface physicalenvironment, and means active to release said source of working energyupon concurrent effective response of both the environment responsivemeans and the signal responsive means.

2. In a well work-ing tool as in claim 1 together with a shiftable stemconstituting a part of the environment responsive means and beingmovable relative to the tool body between inactive and active positionsof said environment responsive means and a stem engageable elementoperable to fix the stem against movement relative to the tool body andthereby maintain said environment responsive means in one of saidpositions.

3. In a well Working tool for travel through a tubing string havingspaced apart signaling stations each providing spaced apart sets ofmagnetic fields spaced diiferently from the fields of other stations,said tool comprising a body, a releasable store of work performingenergy carried by the body and adapted to be electrically brought intoaction and electric control means therefor including first and secondnormally inactive circuit completing devices co-operatively related topreclude energy release unless the devices are concurrently active, saidfirst device being responsive to subsurface environment conditions andthe second device comprising a pair of spaced apart units which areresponsive to magnetic fields of tubing string stations traversed by thetool, and means to condition the spacing between said units to coincidewith the spacing of the magnetic fields of a selected station.

4. In a Well working tool for travel within a tubing string having meansproviding spaced apart sets of spaced apart magnetic fields spaceddifierently in each set, said tool including an electrically releasablesource of working energy, a number of normally inactive control deviceshaving series electrical connection for efifecting release of the energysource when all of said devices are concurrently active, an actuatingmember for one of said devices exposed to well pressure fluids andresponsive to given fluid pressure thereon, a set of magnetic fieldresponsive elements operably connected with theothers of said devices,and selectively set means to present said elements in spaced apartrelation corresponding to the field spacing in any of said sets ofmagnetic fields.

5. In a well working tool for travel within a tubing string having meansproviding spaced apart sets of magnetic fields of like number in eachset and spaced differently in each set, said tool including anelectrically releasable source of energy and control means thereforhaving serially connected circuit closing devices, one of such devicesbeing responsive to given physical environment conditions within atubing string to establish its circuit closing relation and others ofthe devices corresponding in number to tubing string magnetic fields insaid sets and being responsive to said magnetic fields to establishcircuit closing relations, and means to present the last mentioneddevices in spaced apart relations corresponding to field spacingsrespectively for concurrent response thereto.

6. In a Well working tool for travel within a tubing string having meansproviding spaced apart sets of magnetic fields spaced apart differentlyin each set, said tool including an electrically releasable source ofenergy, a. number of normally open circuit control switches arranged forseries connected circuit closing relation to release the energy of saidsource, means responsive to subsurface physical conditions to close oneof said switches, means responsive to magnetic fields to close the otherof said switches, means mounting the others of said switches in spacedapart relation determined by the different spacing of the tubing stringfields of the several sets whereby selected ones of the switches will bespaced apart in matching relations respectively to field spacings of theseveral sets, and means to place selected ones of said other switches inseries circuit relation with said one of said switches.

7. In a well working tool for travel within a tubing string having meansproviding spaced apart sets of magnetic fields spaced apart differentlyin each set, said tool including an electrically releasable source ofenergy, a number of normally open circuit control switches arranged forseries connected circuit closing relation to release the energy of saidsource, means responsive to subsurface physical conditions to close oneof said switches, means responsive to magnetic fields to close the otherof said switches, and means operable to present said other switches inspaced apart relations matching the field spacings of the setsselectively.

8. In a Well tool adapted to be run in a Well and to be actuated uponreceipt of -a signal from a subsurface signaling station, a tool body,an electrically actuated element carried by the body, a first circuitclosing device and a second circuit closing device connected in seriescircuit relation and operative to actuate said element when the devicesare concurrently in circuit closing relation, signal responsive means toeifect circuit closing relation of the first device, and a well fluidpressure responsive control member connected with the second circuitclosing device and shiftably mounted on the tool body for movementbetween circuit opening position and circuit closing position.

9. In a well tool adapted to be run in a well and to be actuated uponreceipt of a signal from a subsurface signaling station, a tool body, anelectrically actuated element carried by the body, a first circuitclosing device and a second circuit closing device connected in seriescircuit relation and operative to actuate said element when the devicesare concurrently in circuit closing relation, signal responsive means toefiect circuit closing relation of the first device, a Well fluidpressure responsive plunger slidably mounted on the tool body andconnected with the second circuit closing device to effect its circuitclosing relation and securing means operable selectively to tie theplunger to the body against slide movement.

10. In a well tool adapted to be run in a well and to be actuated uponreceipt of a signal from a subsurface signaling station, a tool body, anelectrically actuated element carried by the body, a first circuitclosing device and a second circuit closing device connected in seriescircuit relation and operative to actuate said element when the devicesare concurrently in circuit closing relation,

signal responsive means to efiect circuit closing relation of the firstdevice, a well fluid pressure responsive control member connected withthe second circuit closing device and shiftably mounted on the tool bodyfor movement between circuit opening position and circuit closingposition, and an adjustable interlock between the tool body and saidcontrol member operable to hold the control member in one 01 saidpositions.

2,494,256 Muskat et al Jan. "10, 1950 10 Barry Mar. 6, Brokaw et al.Mar. 13, Ring June 28, Wurgler July 1, Ring July 22, Epstein Ian. 13,Young et a1. Dec. 5, Feeser Apr. 3, Rumble May 1,

FOREIGN PATENTS France June 13,

8. IN A WELL TOOL ADAPTED TO BE RUN IN A WELL AND TO BE ACTUATED UPONRECEIPT OF A SIGNAL FROM A SUBSURFACE SIGNALING STATION, A TOOL BODY, ANELECTRICALLY ACTUATED ELEMENT CARRIED BY THE BODY, A FIRST CIRCUITCLOSING DEVICE AND A SECOND CIRCUIT CLOSING DEVICE CONNECTED IN SERIESCIRCUIT RELATION AND OPERATIVE TO ACTUATE SAID ELEMENT WHEN THE DEVICESARE CONCURRENTLY IN CIRCUIT CLOSING RELATION, SIGNAL RESPONSIVE MEANS TOEFFECT CIRCUIT CLOSING RELATION OF THE FIRST DEVICE, AND A WELL FLUIDPRESSURE RESPONSIVE CONTROL MEMBER CONNECTED WITH THE SECOND CIRCUITCLOSING DEVICE AND SHIFTABLY MOUNTED ON THE TOOL BODY FOR MOVEMENTBETWEEN CIRCUIT OPENING POSITION AND CIRCUIT CLOSING POSITION.